Type of Publication: | Journal article |
URI (citable link): | http://nbn-resolving.de/urn:nbn:de:bsz:352-239586 |
Author: | Wiesenfeldt, Helga; Reinmuth, Annette; Barsties, Elke; Evertz, Kaspar; Brintzinger, Hans-Herbert |
Year of publication: | 1989 |
Published in: | Journal of Organometallic Chemistry ; 369 (1989), 3. - pp. 359-370. - ISSN 0022-328X. - eISSN 1872-8561 |
DOI (citable link): | https://dx.doi.org/10.1016/0022-328X(89)85186-1 |
Summary: |
The formation of racemic and meso diastereomers of the disubstituted ansa-zirconocenes (CH3)2Si(1-C5H3-3-R)2ZrCl2 (R = t-butyl, trimethylsilyl, α,α-dimethylbenzyl and 1-phenylcyclohexyl) from dimethylsilanediyl-bridged, symmetrically substituted bis-cyclopentadienyl dianion derivatives and ZrCl4·2THF has been studied under a variety of conditions. Rac/meso ratios close to 1 were obtained in all cases. Similar product ratios were observed for analogous titanium and hafnium complexes with R = trimethylsilyl. A significant increase in the rac/meso product ratio was observed when an additional substituent was present next to the dimethylsilyl bridge as in (CH3)2Si(1-C5H2-3-R-5-CH3)2ZrCl2 (R = CH(CH3)2, C(CH3)3). It is suggested that intermediates with one η1-bound ring ligand control the stereochemical course of the ansa-metallocene formation. The crystal structure of R,S-(CH3)2Si(1-C5H2-3-C(CH3)3-5-CH3)2ZrCl2 is reported.
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Subject (DDC): | 540 Chemistry |
Link to License: | In Copyright |
WIESENFELDT, Helga, Annette REINMUTH, Elke BARSTIES, Kaspar EVERTZ, Hans-Herbert BRINTZINGER, 1989. ansa-metallocene derivatives : XVII. Racemic and meso diastereomers of group IV metallocene derivatives with symmetrically substituted, dimethylsilanediyl-bridged ligand frameworks. Crystal structure of R,S-Me2Si(3-t-Bu-5-MeC5H2)2ZrCl2. In: Journal of Organometallic Chemistry. 369(3), pp. 359-370. ISSN 0022-328X. eISSN 1872-8561. Available under: doi: 10.1016/0022-328X(89)85186-1
@article{Wiesenfeldt1989ansam-23958, title={ansa-metallocene derivatives : XVII. Racemic and meso diastereomers of group IV metallocene derivatives with symmetrically substituted, dimethylsilanediyl-bridged ligand frameworks. Crystal structure of R,S-Me2Si(3-t-Bu-5-MeC5H2)2ZrCl2}, year={1989}, doi={10.1016/0022-328X(89)85186-1}, number={3}, volume={369}, issn={0022-328X}, journal={Journal of Organometallic Chemistry}, pages={359--370}, author={Wiesenfeldt, Helga and Reinmuth, Annette and Barsties, Elke and Evertz, Kaspar and Brintzinger, Hans-Herbert} }
1-s2.0-0022328X89851861Wiesenfeld.pdf | 1237 |